The fertile window is the period during which a person can get pregnant. This window is the day an egg is released from the ovaries (ovulation) and the five days beforehand. This time period offers couples looking to conceive the best chance of getting pregnant naturally.

What is a fertile window?

The fertile window, also known as the “pregnancy window,” refers to the days during the menstrual cycle in which a person is most likely to get pregnant. The fertile window lasts around six days, including the day the egg is released from the ovaries and five days beforehand. Once the egg is released, it is in the fallopian tubes for 24 hours, while sperm can survive up to five days.

There is a common misconception that pregnancy can happen at any moment. This, however, is untrue; egg and sperm need to come together at the right time in the fallopian tubes to fertilize and develop into an embryo.
Couples trying to conceive are advised to engage in sexual intercourse during this six-day window to increase their chances of achieving pregnancy. Recent studies have shown that the likelihood of conception increases significantly in the three days leading up to and including ovulation.

Fertile window and  male fertility

Couples who are trying to conceive, especially those with male-factor infertility issues and couples that have trouble conceiving, should aim to have sex multiple times — every 1–2 days — during the fertile window. This offers the best chance at getting pregnant.

As menstrual cycles vary from person to person, it is difficult to predict ovulation universally. Those with perfect 28-day cycles will ovulate on day 14, and consequently, the fertile window would fall between days 9 and 14. However, the window will fall earlier in shorter cycles, and later in longer ones.

Determining the fertile window

Determining a person’s fertile window will require tracking their menstrual cycle and signs of ovulation. Clinical and at-home tests, such as urine hormone tests, can be done to determine when ovulation is about to take place, but other indicators can also help establish the fertile window, including a rise in basal body temperature and a thinning in the consistency of cervical mucus.